“You say there are two types of people?”
“Yes, those who separate people into two groups and those that don’t.”
“Wrong. There are three groups:
Those who separate people into three groups.
Those who don’t separate people into groups.
Those who can’t decide.”
“Wait a minute, what about people who separate people into two groups?”
“Oh. Okay, then there are four groups.”
“Aren’t you then separating people into four groups?”
“So then there’s a fifth group, right?”
“You know, the problem is these idiots who can’t make up their minds.”